More and more people are moving to cities and turning to public transit, so what happens when these aging systems can't handle the load of increasing masses?
It takes a lot of people skills and knowledge of the intricacies of labor contracts to be a Federal mediator, like those called in to try to resolve the BART strike in the San Francisco Bay Area.
BART employees and management are in the midst of a 60-day cooling-off period, but with little progress reported so far, another strike could be coming.
The strike has laid bare a tricky cultural divide in the Bay Area, between traffic-weary tech workers who drive the local economy, and blue collar transit workers who feel left behind.
